Androgen drives melanoma invasiveness and metastatic spread by inducing tumorigenic fucosylation.

Melanoma incidence and mortality rates are historically higher for men than women. Although emerging studies have highlighted tumorigenic roles for the male sex hormone androgen and its receptor (AR) in melanoma, cellular and molecular mechanisms underlying these sex-associated discrepancies are poorly defined. Here, we delineate a previously undisclosed mechanism by which androgen-activated AR transcriptionally upregulates fucosyltransferase 4 (FUT4) expression, which drives melanoma invasiveness by interfering with adherens junctions (AJs). Global phosphoproteomic and fucoproteomic profiling, coupled with in vitro and in vivo functional validation, further reveal that AR-induced FUT4 fucosylates L1 cell adhesion molecule (L1CAM), which is required for FUT4-increased metastatic capacity. Tumor microarray and gene expression analyses demonstrate that AR-FUT4-L1CAM-AJs signaling correlates with pathological staging in melanoma patients. By delineating key androgen-triggered signaling that enhances metastatic aggressiveness, our findings help explain sex-associated clinical outcome disparities and highlight AR/FUT4 and its effectors as potential prognostic biomarkers and therapeutic targets in melanoma.

Histone Demethylase KDM3 (JMJD1) in Transcriptional Regulation and Cancer Progression.

Methylation of histone H3 lysine 9 (H3K9) is a repressive histone mark and associated with inhibition of gene expression. KDM3 is a subfamily of the JmjC histone demethylases. It specifically removes the mono- or di-methyl marks from H3K9 and thus contributes to activation of gene expression. KDM3 subfamily includes three members: KDM3A, KDM3B and KDM3C. As KDM3A (also known as JMJD1A or JHDM2A) is the best studied, this chapter will mainly focus on the role of KDM3A-mediated gene regulation in the biology of normal and cancer cells. Knockout mouse studies have revealed that KDM3A plays a role in the physiological processes such as spermatogenesis, metabolism and sex determination. KDM3A is upregulated in several types of cancers and has been shown to promote cancer development, progression and metastasis. KDM3A can enhance the expression or activity of transcription factors through its histone demethylase activity, thereby altering the transcriptional program and promoting cancer cell proliferation and survival. We conclude that KDM3A may serve as a promising target for anti-cancer therapies.

SMAD3 promotes expression and activity of the androgen receptor in prostate cancer.

Overexpression of androgen receptor (AR) is the primary cause of castration-resistant prostate cancer, although mechanisms upregulating AR transcription in this context are not well understood. Our RNA-seq studies revealed that SMAD3 knockdown decreased levels of AR and AR target genes, whereas SMAD4 or SMAD2 knockdown had little or no effect. ChIP-seq analysis showed that SMAD3 knockdown decreased global binding of AR to chromatin. Mechanistically, we show that SMAD3 binds to intron 3 of the AR gene to promote AR expression. Targeting these binding sites by CRISPRi reduced transcript levels of AR and AR targets. In addition, ∼50% of AR and SMAD3 ChIP-seq peaks overlapped, and SMAD3 may also cooperate with or co-activate AR for AR target expression. Functionally, AR re-expression in SMAD3-knockdown cells partially rescued AR target expression and cell growth defects. The SMAD3 peak in AR intron 3 overlapped with H3K27ac ChIP-seq and ATAC-seq peaks in datasets of prostate cancer. AR and SMAD3 mRNAs were upregulated in datasets of metastatic prostate cancer and CRPC compared with primary prostate cancer. A SMAD3 PROTAC inhibitor reduced levels of AR, AR-V7 and AR targets in prostate cancer cells. This study suggests that SMAD3 could be targeted to inhibit AR in prostate cancer.

Independent Evolution of Sex Chromosomes and Male Pregnancy-Related Genes in Two Seahorse Species.

Unlike birds and mammals, many teleosts have homomorphic sex chromosomes, and changes in the chromosome carrying the sex-determining locus, termed "turnovers", are common. Recent turnovers allow studies of several interesting questions. One question is whether the new sex-determining regions evolve to become completely non-recombining, and if so, how and why. Another is whether (as predicted) evolutionary changes that benefit one sex accumulate in the newly sex-linked region. To study these questions, we analyzed the genome sequences of two seahorse species of the Syngnathidae, a fish group in which many species evolved a unique structure, the male brood pouch. We find that both seahorse species have XY sex chromosome systems, but their sex chromosome pairs are not homologs, implying that at least one turnover event has occurred. The Y-linked regions occupy 63.9% and 95.1% of the entire sex chromosome of the two species and do not exhibit extensive sequence divergence with their X-linked homologs. We find evidence for occasional recombination between the extant sex chromosomes that may account for their homomorphism. We argue that these Y-linked regions did not evolve by recombination suppression after the turnover, but by the ancestral nature of the low crossover rates in these chromosome regions. With such an ancestral crossover landscape, a turnover can instantly create an extensive Y-linked region. Finally, we test for adaptive evolution of male pouch-related genes after they became Y-linked in the seahorse.

Co-Targeting ErbB Receptors and the PI3K/AKT Axis in Androgen-Independent Taxane-Sensitive and Taxane-Resistant Human Prostate Cancer Cells.

Using two representative models of androgen-independent prostate cancer (PCa), PC3 and DU145, and their respective paclitaxel- and docetaxel-resistant derivatives, we explored the anti-tumor activity of targeting the ErbB receptors and AKT using small-molecule kinase inhibitors. These cells manifest varying degrees of neuroendocrine differentiation characteristics and differ in their expression of functional PTEN. Although the specific downstream signaling events post the ErbB receptor and AKT co-targeting varied between the PC3- and DU145-lineage cells, synergistic anti-proliferative and enhanced pro-apoptotic responses occurred across the wild-type and the taxane-resistant cells, independent of their basal AKT activation state, their degree of paclitaxel- or docetaxel-resistance, or whether this resistance was mediated by the ATP Binding Cassette transport proteins. Dual targeting also led to enhanced anti-tumor responses in vivo, although there was pharmacodynamic discordance between the PCa cells in culture versus the tumor xenografts in terms of the relative activation and inhibition states of AKT and ERK under basal conditions and upon AKT and/or ErbB targeting. The consistent inhibition, particularly of AKT, occurred both in vitro and in vivo, independent of the underlying PTEN status. Thus, co-targeting AKT with ErbB, and possibly other partners, may be a useful strategy to explore further for potential therapeutic effect in advanced PCa.

Activin A is a novel chemoattractant for migration of microglial BV2 cells.

BACKGROUND: Microglia are involved in many neurodegenerative diseases and repairment of traumatic injury to the CNS. Activin A is a neurotrophic and neuroprotective factor that can regulate the activities of macrophages/microglia. However, the effects of activin A on the migration of microglia are still unclear. In this study, the role of activin A in regulation of the microglia migration was investigated with the murine microglial BV2 cell. METHODS: The levels of cytokines were detected by enzyme-linked immunosorbent assay (ELISA). The protein expression was examined by Western blotting. The adhesion of BV2 cells was assayed by real-time cell analysis (RTCA). The migration of BV2 cells was determined by transwell chamber and microfluidics device. Smad3 was overexpressed or knocked down in BV2 cells by transfection of Smad3 or Smad3 shRNA-expressing plasmids. RESULTS: Activin A inhibited the release of nitric oxide (NO) and inflammatory cytokines of TNF-α and IL-6 and the expression of TNF-α and IL-6 mRNA by BV2 cells. In contrast, activin A promoted the production of TGF-ß1. Activin A inhibited adhesion, promoted wound healing and migration which is related to the expression of N-cadherin and E-cadherin expression. Additionally, Smad3 overexpression in BV2 cells decreased the levels of TNF-α and IL-6, and promoted the wound healing, whereas Smad3 knockdown showed the opposite effects. CONCLUSIONS: These findings revealed that activin A regulated the biological behavior of BV2 cells via Smad3 signaling, suggesting that activin A may serve as a potential treatment target for neuroinflammation and glia scar formation in nervous system.

High-dimension to high-dimension screening for detecting genome-wide epigenetic and noncoding RNA regulators of gene expression.

MOTIVATION: The advancement of high-throughput technology characterizes a wide variety of epigenetic modifications and noncoding RNAs across the genome involved in disease pathogenesis via regulating gene expression. The high dimensionality of both epigenetic/noncoding RNA and gene expression data make it challenging to identify the important regulators of genes. Conducting univariate test for each possible regulator-gene pair is subject to serious multiple comparison burden, and direct application of regularization methods to select regulator-gene pairs is computationally infeasible. Applying fast screening to reduce dimension first before regularization is more efficient and stable than applying regularization methods alone. RESULTS: We propose a novel screening method based on robust partial correlation to detect epigenetic and noncoding RNA regulators of gene expression over the whole genome, a problem that includes both high-dimensional predictors and high-dimensional responses. Compared to existing screening methods, our method is conceptually innovative that it reduces the dimension of both predictor and response, and screens at both node (regulators or genes) and edge (regulator-gene pairs) levels. We develop data-driven procedures to determine the conditional sets and the optimal screening threshold, and implement a fast iterative algorithm. Simulations and applications to long noncoding RNA and microRNA regulation in Kidney cancer and DNA methylation regulation in Glioblastoma Multiforme illustrate the validity and advantage of our method. AVAILABILITY AND IMPLEMENTATION: The R package, related source codes and real datasets used in this article are provided at https://github.com/kehongjie/rPCor. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Isolation and identification of a new strain of nervous necrosis virus from the big-belly seahorse Hippocampus abdominalis.

BACKGROUND: Betanodaviruses, members of the Nodaviridae family, are the causative agents of viral nervous necrosis in fish, resulting in great economic losses worldwide. METHODS: In this study, we isolated a virus strain named seahorse nervous necrosis virus (SHNNV) from cultured big-belly seahorses Hippocampus abdominalis in Xiamen city, Fujian Province, China. Virus isolation, PCR detection, phylogenetic analysis, qRT-PCR, fluorescence in situ hybridization and histology were used for virus identification and analysis of virus histopathology. Furthermore, an artificial infection experiment was conducted for virulence testing. RESULTS: Brain and eye tissue homogenates of diseased big-belly seahorses were inoculated onto a grouper spleen (GS) cell monolayer at 28 °C. Tissue homogenates induced obvious cytopathic effects in GS cells. PCR and sequencing analyses revealed that the virus belonged to Betanodavirus and shared high sequence identity with red-spotted grouper nervous necrosis virus isolates. qRT-PCR and fluorescence in situ hybridization revealed that SHNNV mainly attacked the brain and eye. Histopathological examination revealed that the virus led to cytoplasmic vacuolation in the brain and retinal tissues. Infection experiments confirmed that SHNNV was highly infectious, causing massive death in big-belly seahorses. CONCLUSION: A novel seahorse betanodavirus from the big-belly seahorse cultured in China was discovered. This finding will contribute to the development of efficient strategies for disease management in aquaculture.

Urinary exosome-based androgen receptor-variant 7 detection in metastatic castration-resistant prostate cancer patients.

Background: Androgen receptor variant 7 (AR-V7) detection provides important information for the clinical management of abiraterone in metastatic castration-resistant prostate cancer (mCRPC). We performed a non-invasive urine-derived exosomal AR-V7 analysis of mCRPC patients. Methods: A total of 34 mCRPC patients were recruited including 16 patients treated with abiraterone (ABI) with stable prostate-specific antigen (PSA)/radiograph response (the ABI-Sta group) and 18 were resistant to abiraterone (the ABI-Res group). Urine was collected from patients and healthy control patients for the analysis. Exosomal ribonucleic acid was isolated from urine. Urinary exosome-based androgen receptor-variant 7 was detected by quantitative real-time polymerase chain reaction assay. Characteristics of patients and survival data were collected. The correlation between AR-V7 expression and the therapeutic effect/survival outcomes of abiraterone was analyzed. Results: Urine is the ideal biological sample for exosome separation and AR full-length analysis. Positive urine-derived exosomal AR-V7 was detected in 32.4% (11 of 34) of the mCRPC patients' urine samples. Positive AR-V7 was more common in the ABI-Res patients than the ABI-Sta patients (50.0% vs. 12.5%, respectively; P=0.009), and was associated with a higher PSA progression rate and poorer overall survival (OS) (P=0.0031, and P=0.0012, respectively). Conclusions: The present study showed that the detection of urine-derived exosomal AR-V7 provides a sensitive and feasible clinical workflow. The predicting role of urine-derived exosomal AR-V7 in mCRPC patients should be further verified using studies with greater sample sizes.

Histone demethylase JMJD1A in cancer progression and therapeutic resistance.

JMJD1A (also called lysine demethylase 3A [KDM3A]) belongs to the Jumonji C family of histone demethylases. It specifically removes the repressive mono- or di-methyl marks from histone H3 at lysine 9 and thus contributes to the activation of gene transcription. JMJD1A plays a key role in a variety of biological processes such as spermatogenesis, metabolism, sex determination, and stem cell activity. JMJD1A is upregulated in various types of cancers and can promote cancer development, progression, and therapeutic resistance. JMJD1A can epigenetically regulate the expression or activity of transcription factors such as c-Myc, androgen receptor (AR), estrogen receptor (ER), ß-catenin, and so on. Expression and activity of JMJD1A in cancer cells can be regulated at transcriptional, post-transcriptional, and post-translational levels. Targeting JMJD1A may repress the oncogenic transcription factors as a potential anticancer therapy.

Genome and gene evolution of seahorse species revealed by the chromosome-level genome of Hippocampus abdominalis.

Seahorses belong to the teleost family Syngnathidae that evolved a distinct body plan and unique male pregnancy compared to other teleosts. As a classic model for studying evolution of viviparity and sexual selection of teleosts, seahorse species still lack a publicly available high-quality reference genome. Here, we generated the genome assembly of the big-belly seahorse, Hippocampus abdominalis with long-read and Hi-C technologies. We managed to place over 99% of the total length of 444.7 Mb of assembled genome into 21 linkage groups with almost no gaps. We reconstructed a phylogenomic tree with the big-belly seahorse genome and other representative Syngnathidae and teleost species. We also reconstructed the historical population dynamics of four representative Syngnathidae species. We found the gene families that underwent expansion or contraction in the Syngnathidae ancestor were enriched for immune-related or ion transporter gene ontology terms. Many of these genes were also reported to show a dynamic expression pattern during the pregnancy stages of H. abdominalis. We also identified putative positively selected genes in the Syngnathidae ancestor or in H. abdominalis, whose mouse mutants are enriched for abnormal craniofacial and limb morphological phenotypes. Overall, our study provides an important genome resource for evolutionary and developmental studies of seahorse species, and candidate genes for future experimental works.

Identification of Prognostic Signature and Gliclazide as Candidate Drugs in Lung Adenocarcinoma.

BACKGROUND: Lung adenocarcinoma (LUAD) is the most common pathological type of lung cancer, with high incidence and mortality. To improve the curative effect and prolong the survival of patients, it is necessary to find new biomarkers to accurately predict the prognosis of patients and explore new strategy to treat high-risk LUAD. METHODS: A comprehensive genome-wide profiling analysis was conducted using a retrospective pool of LUAD patient data from the previous datasets of Gene Expression Omnibus (GEO) including GSE18842, GSE19188, GSE40791 and GSE50081 and The Cancer Genome Atlas (TCGA). Differential gene analysis and Cox proportional hazard model were used to identify differentially expressed genes with survival significance as candidate prognostic genes. The Kaplan-Meier with log-rank test was used to assess survival difference. A risk score model was developed and validated using TCGA-LUAD and GSE50081. Additionally, The Connectivity Map (CMAP) was used to predict drugs for the treatment of LUAD. The anti-cancer effect and mechanism of its candidate drugs were studied in LUAD cell lines. RESULTS: We identified a 5-gene signature (KIF20A, KLF4, KRT6A, LIFR and RGS13). Risk Score (RS) based on 5-gene signature was significantly associated with overall survival (OS). Nomogram combining RS with clinical pathology parameters could potently predict the prognosis of patients with LUAD. Moreover, gliclazide was identified as a candidate drug for the treatment of high-RS LUAD. Finally, gliclazide was shown to induce cell cycle arrest and apoptosis in LUAD cells possibly by targeting CCNB1, CCNB2, CDK1 and AURKA. CONCLUSION: This study identified a 5-gene signature that can predict the prognosis of patients with LUAD, and Gliclazide as a potential therapeutic drug for LUAD. It provides a new direction for the prognosis and treatment of patients with LUAD.

N6-Methyladenosine RNA Demethylase FTO Promotes Gastric Cancer Metastasis by Down-Regulating the m6A Methylation of ITGB1.

Abnormal RNA m6A methylation is known to lead to the occurrence and progression of multiple cancers including gastric cancer (GC). However, the integrative effects of all m6A methylation regulators on GC prognosis are unclear. Our research aimed to globally analyze the prognosis values of all 33 m6A RNA methylation regulators in GC by univariate and multivariate Cox regression analyses. Among all 33 m6A RNA methylation regulators, fat mass and obesity-associated protein (FTO), an m6A demethylase, was identified as a key prognostic risk factor on overall survival (OS) of GC patients. It was found that FTO could promote GC cell migration and invasion abilities, and we predicted that ITGB1 was a demethylated target of FTO. Knockdown (KD) of FTO significantly down-regulated ITGB1 expression at both mRNA and protein levels and augmented ITGB1 mRNA m6A modification level. Moreover, overexpression (OE) of ITGB1 could partially reverse FTO-KD-inhibited migration and invasion of GC cells. Our study found that FTO was an independent risk factor for overall survival (OS) of GC patients and FTO could promote GC metastasis by upregulating the expression of Integrin ß1(ITGB1) via decreasing its m6A level. These results indicated that FTO can be a potent GC biomarker for prognosis prediction as well as a potential target in GC treatment.

Activin A as a Novel Chemokine Induces Migration of L929 Fibroblasts by ERK Signaling in Microfluidic Devices.

Activin A, a member of the transforming growth factor-beta (TGF-ß) superfamily, contributes to tissue healing and fibrosis. As the innate tissue cells, fibroblasts also play an important role in wound healing and fibrosis. Herein, this study was aimed to investigate how activin A exhibited regulatory effects on adhesion and migration of fibroblasts. We found that activin A induced the migration of fibroblast cell line L929 cells in transwell chamber and microfluidic device. Activin A also promoted L929 cells adhesion, but did not affect L929 cells viability or proliferation. In addition, activin A induced α-SMA expression and TGF-ß1 release, which were factors closely related to tissue fibrosis, but had no effect on IL-6 production, a pro-inflammatory cytokine. Furthermore, activin A elevated calcium levels in L929 cells and increased p-ERK protein levels. Activin A-induced migration of L929 cells was attenuated by ERK inhibitor FR180204. To conclude, these data indicated that activin A as a novel chemokine induced the chemotactic migration of L929 cells via ERK signaling and possessed the pro-fibrosis role. These findings provide a new insight into understanding of activin A in tissue fibrosis.

Bioinformatics-Based Identification of HDAC Inhibitors as Potential Drugs to Target EGFR Wild-Type Non-Small-Cell Lung Cancer.

Patients with EGFR-mutant non-small-cell lung cancer (NSCLC) greatly benefit from EGFR-tyrosine kinase inhibitors (EGFR-TKIs) while the prognosis of patients who lack EGFR-sensitive mutations (EGFR wild type, EGFR-WT) remains poor due to a lack of effective therapeutic strategies. There is an urgent need to explore the key genes that affect the prognosis and develop potentially effective drugs in EGFR-WT NSCLC patients. In this study, we clustered functional modules related to the survival traits of EGFR-WT patients using weighted gene co-expression network analysis (WGCNA). We used these data to establish a two-gene prognostic signature based on the expression of CYP11B1 and DNALI1 by combining the least absolute shrinkage and selection operator (LASSO) algorithms and Cox proportional hazards regression analysis. Following the calculation of risk score (RS) based on the two-gene signature, patients with high RSs showed a worse prognosis. We further explored targeted drugs that could be effective in patients with a high RS by the connectivity map (CMap). Surprisingly, multiple HDAC inhibitors (HDACis) such as trichostatin A (TSA) and vorinostat (SAHA) that may have efficacy were identified. Also, we proved that HDACis could inhibit the proliferation and metastasis of NSCLC cells in vitro. Taken together, our study identified prognostic biomarkers for patients with EGFR-WT NSCLC and confirmed a novel potential role for HDACis in the clinical management of EGFR-WT patients.

Succinylation Regulators Promote Clear Cell Renal Cell Carcinoma by Immune Regulation and RNA N6-Methyladenosine Methylation.

Succinylation is a newly discovered and multienzyme-regulated post-translational modification (PTM) that is associated with the initiation and progression of cancer. Currently, no systematic analyses on the role of succinylation regulators in tumors have been reported. In this study, we performed a comprehensive pan-cancer analysis on four well-known succinylation regulators (CPT1A, KAT2A, SIRT5, and SIRT7). We found that these regulators played specific and critical roles in the prognosis of clear cell renal cell carcinoma (ccRCC). We constructed a risk score (RS) based on two independent prognostic prediction factors, CPT1A and KAT2A, and subsequently developed a nomogram model containing the RS, which showed good accuracy in the prediction of overall survival (OS) in ccRCC patients. Furthermore, we used the similar expression pattern of four succinylation regulators according to consensus clustering analysis to divide the patients into three clusters that exhibited prominently different OS as well as clinicopathological characteristics. Differently expressed genes (DEGs) and pathway enrichment analyses of three clusters indicated that succinylation regulators might promote malignant progression of ccRCC by regulating the infiltration of immune cells and RNA N6-methyladenosine (m6A) methylation. Importantly, our data suggest that CPT1A and SIRT5 might up-regulate and down-regulate the expression of LRPPRC and EIF3B, respectively. Our study systematically analyzed the prognostic predictive values of four succinylation regulators and revealed their potential mechanisms in ccRCC aggressiveness. These data provide new insight into the understanding of succinylation modification and present clinical evidence for its role in ccRCC treatments.

LncRNA APCDD1L-AS1 induces icotinib resistance by inhibition of EGFR autophagic degradation via the miR-1322/miR-1972/miR-324-3p-SIRT5 axis in lung adenocarcinoma.

BACKGROUND: Epidermal growth factor receptor-tyrosinase kinase inhibitor (EGFR-TKI) resistance is the major obstacle in the treatment of lung adenocarcinoma (LUAD) patients harboring EGFR-sensitive mutations. However, the long non-coding RNAs (lncRNAs) related to EGFR-TKIs resistance and their functional mechanisms are still largely unknown. This study aimed to investigate the role and regulatory mechanism of lncRNA APCDD1L-AS1 in icotinib resistance of lung cancer. METHODS: Molecular approaches including qRT-PCR, MTT assay, colony formation, RNA interference and cell transfection, RNA immunoprecipitation (RIP), dual luciferase reporter assay, RNA fluorescence in situ hybridization, TUNEL assay, flow cytometry, immunoblotting, xenograft model and transcriptome sequencing were used to investigate the mechanism of APCDD1L-AS1 in icotinib resistance. RESULTS: A novel lncRNA, APCDD1L-AS1 was identified as the most significantly upregulated lncRNA in icotinib-resistant LUAD cells by the transcriptome sequencing and differential lncRNA expression analysis. We found that APCDD1L-AS1 not only promoted icotinib resistance, but also upregulated the protein expression level of EGFR. Mechanistically, APCDD1L-AS1 promoted icotinib resistance and EGFR upregulation by sponging with miR-1322/miR-1972/miR-324-3p to remove the transcription inhibition of SIRT5. Furthermore, SIRT5 elevated EGFR expression and activation by inhibiting the autophagic degradation of EGFR, finally promoting icotinib resistance. Consistently, the autophagy initiator rapamycin could decrease EGFR levels and increase the sensitivity of icotinib-resistant LUAD cells to icotinib. CONCLUSION: APCDD1L-AS1 could promote icotinib resistance by inhibiting autophagic degradation of EGFR via the miR-1322/miR-1972/miR-324-3p-SIRT5 axis. The combination of autophagy initiator and EGFR-TKIs might serve as a potential new strategy for overcoming EGFR-TKIs resistance in LUAD patients.

Lung adenocarcinoma-specific three-integrin signature contributes to poor outcomes by metastasis and immune escape pathways.

BACKGROUND: Inhibitors targeting integrins (ITGs) are applied as a novel strategy for cancers including lung cancer; however, the heterogeneity of ITG subunits might explain why ITG-targeted inhibitors only show limited efficacy for a small group of lung cancer patients. MATERIALS AND METHODS: RNA-Seq data of lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC) patients were obtained from the TCGA database. Cox regression analysis was performed to construct the prognostic signature and generate the nomogram combined with pathologic stages (pStage). GEO datasets were used for verification. The related biological functions were analyzed by Gene Set Enrichment Analysis (GSEA) software and the TIMER database. RESULTS: By Cox regression analysis of 30 ITG subunits, ITG subunit alpha 5 (ITGA5), ITG subunit alpha 6 (ITGA6), and ITG subunit alpha L (ITGAL) were identified as the prognostic factors in LUAD, which were included in the construction of a LUAD-specific 3-ITG signature. Following the calculation of risk score (RS) of each patient based on 3-ITG signature, patients with high RS in LUAD were found to exhibit worse prognosis, especially in early stage. Nomogram combined with RS and pStage could predict the prognosis of LUAD patients accurately. Mechanism exploration by GSEA showed that metastasis-related microenvironmental pathways were significantly enriched in the high-RS group. An elevated expression of ITGA5 was mainly associated with the promotion of cell migration and invasion, while the high expression of ITGAL had a strong positive correlation with the capability of recognizing and killing cancer cells. CONCLUSIONS: Three-ITG signature could improve the prediction ability combined with pStage in LUAD and might contribute to poor prognosis by metastasis and immune escape-related pathways.